Process of preparing basic dyestuffs derived from indoline bases



Patented July 11, 1933 UNITED STATES j i i -1",9*17v,475

OTTMAR' 'WAI-IL; or, LEVERKUsEN-on-rrin-arrrrin Gem/nae; AssreNon-ro GENERAL ANILINE womrs, mo, ornn'w YORK, 'N'."Y:, A-GOBPORATION or DELAWARE PRooEss oF PREPARING; BASIC r-Ynsrurns nnsIvEn rnoivirnnonrirn BASES N0 Drawing. Application-filed 0ct0ber18, 1930, Seria1fio; asavo'aeaafiii ea-may November s, 1929.)

The present invention relates to aprocess of preparing basic dyestuffs derived from indoline bases and to the new product obtainable thereby.

In U. S. Letters Patent 1,755,678 I have described new dyestuifs derived from indoline bases of the general formula a? meaning an organic or inorganic acid radicle and whereln the benzene nucle may be further substitutedf According to said Letters Patent these dyestuffs are prepared by treating a 1.3;3-trialkyl-Q-methylene indoline (such as 1.3.3-

trimethyl-2-methylene-indoline) offthe formula alkyl wherein the benzene nucleus maybe substituted or not or a salt, thereof of the formula:

Henide of nitrous acid andone molecule of a 1.3.3-trialkyl-2-methylene-indoline to react upon each other i in an inert organic solvent, such as benzene or carbontetrachloride,"

- H [I p I whereby are1rormed 'nltros'o compounds according to the following equation:

a e ca1k 1 +NOHa1- alkyl 7 V (Hal-:Halogen) o -om No @These nitroso compounds which are well crystallizing, stable substances then are allowed to react with a further molecule of the same or a difierent 1.3.3-trialkyl-2-methyleneindoline 'inthe presence of an organic acid anhydride, as for example, acetic anhydride whichserv'es as condensing agent, thus, when using different 1.3.3-trialkyl-2-1nethyleneindole compoundsasymmetrical dyestuffs be ing obtained when preparing the symmetrica'l' dyestuffs it is of advantage to perform" the whole process in one step, that means to dissolve the 1.3.3-trialkyl 2-methylene indoline compound in the condensing agent, especiallyacetic acid anhydride, and introducing the requisite quantity of halogenide of nitrous acid; in'this manner the forma tion of the nitroso compound is immediately followed by the condensation to the dyestuff.

The whole process probably proceeds ac cording to the following scheme:

The invention is illustrated by the following examples Emample J.In a solution of 1 molecule of 1.3.3-trimethyl-2-methylene-indoline in carbon tetrachloride 1 molecule of nitrosylchloride is introduced. The hydrochloric acid salt of the 1.3.3-trimethyl-2-nitrosomethylene indoline precipitates and is either isolated by filtering with suction or agitated with Water.

It can be obtained by salting out of the aqueous solution in weakly yellowish colored crystals of a melting point of'195 C. I

One part by weight of the product thus'obtained is mixed with one part by weight of 1.3.3-trimethyl-2-methylene indoline in about 5 parts by weight of acetic acid anhydride until the amount of the separating yellow dyestufi formed does no more increase. In order to decompose the acetic acid anhydride water is added and the dyestuif is precipitated by common salt and zinc chloride as zinc chloride double salt.

The dyestufi of the formula is identical to the one described in Example 1 of U. S. Patent No. 1,755,678.

Eula mph 2.5 parts by weight of 1.3.3-trimetl1yl-2-methylene indoline are dissolved in about 20 parts by weight of acetic acid anhydride and, advantageously while cooling, 1 part by weight of nitrosylchloride is intro duced.

The working up follows as in Example 1 and the same yellow dyestufi is obtained.

Example 3.-1 part by weight of hydrochloric acid salt of the 1,3,8-trimethyl-2-nitrosomethylene indoline is introduced with 1 part by weight of 1.3.3-trimethyl-2-methylene-5-amido indoline into 5 parts by weight of acetic acid anhydride, advantageously at a temperature of about 40 C. slowly for about 34 hours, and stirred until the formation of the dyestuif is finished. In order to obtain decomposition of the anhydride, water is added and the dyestufl' is precipitated with zinc chloride and common salt.

By recrystallizing from water the dyestufi is obtained pure and gives, dyed according to the usual methods for basic dyestufls, on tanned cotton an orange-yellowish color with a more reddish tint than the dyestufl' described in Example 1. Obviously the zinc chloride double salt of the unsymmetrical dyestufi' is present of the formula:

1. The process which comprises causing a 1.3.3-trimethyl-2-methylene indoline and an about equimolecular portion of a halogenide of nitrous acid to react upon each other and reacting upon the intermediate product formed with an about equimolecular portion of a 1.3.3-trimethyl-2-methylene indoline in the presence of acetic acid anhydride.

2. The process WlllChCOlllPI'lSGS dissolving 5 parts by weight of 1.3.3-trimethyl-2-methylene indoline'in about 20 parts by Weight of acetic acid anhydride and introducing into the solution 1 part by weight of nitrosylchloride. I

V 3. The dyestuff corresponding probably to the formula:

dyeing tanned cotton in orange-yellowish color of good fastness to light.

In testimony whereof, I aflix my signature.

OTTMAR WAHL. 

